From: Jessica Yu jeyu@kernel.org
[ Upstream commit e0328feda79d9681b3e3245e6e180295550c8ee9 ]
In the arm64 module linker script, the section .text.ftrace_trampoline is specified unconditionally regardless of whether CONFIG_DYNAMIC_FTRACE is enabled (this is simply due to the limitation that module linker scripts are not preprocessed like the vmlinux one).
Normally, for .plt and .text.ftrace_trampoline, the section flags present in the module binary wouldn't matter since module_frob_arch_sections() would assign them manually anyway. However, the arm64 module loader only sets the section flags for .text.ftrace_trampoline when CONFIG_DYNAMIC_FTRACE=y. That's only become problematic recently due to a recent change in binutils-2.35, where the .text.ftrace_trampoline section (along with the .plt section) is now marked writable and executable (WAX).
We no longer allow writable and executable sections to be loaded due to commit 5c3a7db0c7ec ("module: Harden STRICT_MODULE_RWX"), so this is causing all modules linked with binutils-2.35 to be rejected under arm64. Drop the IS_ENABLED(CONFIG_DYNAMIC_FTRACE) check in module_frob_arch_sections() so that the section flags for .text.ftrace_trampoline get properly set to SHF_EXECINSTR|SHF_ALLOC, without SHF_WRITE.
Signed-off-by: Jessica Yu jeyu@kernel.org Acked-by: Will Deacon will@kernel.org Acked-by: Ard Biesheuvel ardb@kernel.org Link: http://lore.kernel.org/r/20200831094651.GA16385@linux-8ccs Link: https://lore.kernel.org/r/20200901160016.3646-1-jeyu@kernel.org Signed-off-by: Catalin Marinas catalin.marinas@arm.com Signed-off-by: Sasha Levin sashal@kernel.org --- arch/arm64/kernel/module-plts.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/arch/arm64/kernel/module-plts.c b/arch/arm64/kernel/module-plts.c index b182442b87a32..426018ebb7007 100644 --- a/arch/arm64/kernel/module-plts.c +++ b/arch/arm64/kernel/module-plts.c @@ -270,8 +270,7 @@ int module_frob_arch_sections(Elf_Ehdr *ehdr, Elf_Shdr *sechdrs, mod->arch.core.plt_shndx = i; else if (!strcmp(secstrings + sechdrs[i].sh_name, ".init.plt")) mod->arch.init.plt_shndx = i; - else if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE) && - !strcmp(secstrings + sechdrs[i].sh_name, + else if (!strcmp(secstrings + sechdrs[i].sh_name, ".text.ftrace_trampoline")) tramp = sechdrs + i; else if (sechdrs[i].sh_type == SHT_SYMTAB)